Broadly, the present invention relates to grain having increased oil and increased protein and amino acids, increased total phosphorus bioavailability and decreased phytic acid. This grain can be used as feedstuffs for animals. More particularly, this invention relates to grain based feed that provide improved animal nutrition, and reduces the environmental impact of animal production.
Over the last fifty years, approaches toward providing animal nutrition have changed. No longer are the animals fed whatever grain or forage may be available. Instead, the diets of animals are closely monitored for total nutrition value, and for cost. The animal on the diet is monitored, for quality and performance characteristics, and for the environmental impact of the waste from the animal. The information gathered is employed to adjust the feed to increase nutrition value of the feed and the animal performance characteristics while decreasing the cost and environmental impact.
Cereals and fats are used in feeding programs for nonruminants such as swine and poultry to provide a nutritional source of calories. The ratio of cereals to supplements, such as vitamins, minerals and fats, have changed across years in an attempt to maximize feeding efficiency of the animals. The feeding efficiency (the feed conversion ratio) or how much feed is required to produce one pound of animal weight is determined by a combination of matching the genetic potential of the animal, and the nutrients supplied to the animal. As the feed conversion ratio has risen due to genetic enhancements, the mineral nutrient requirements in the feed have risen to assure a complete and heathy diet.
Since an animal""s ability to feed limits the amount of nutrients and calories it can consume, the feed industry has had to develop ways to make feeds that are more highly caloric. To increase the caloric density of the feed, producers have added fat to the feed. Fat has often been added to the feed in the form of a liquid. Fat has the advantage of supplying calories to each mouthful of feed. However, adding fat to feed has some disadvantages such as costs, added labor and technical difficulties with automatic feeding systems. Additionally, the fat is often of poor quality, thus reducing the overall quality of the feed.
To reduce the use of liquid fat in feeds, the industry has tried increasing the oil content of the grain used in the feeds. The Dupont company has developed and commercialized high oil corn as a method for increasing the oil content of feed. Other companies have developed corn that has more oil than no. 2 yellow dent corn but less than Dupont""s high oil corn. High oil and elevated oil corn is herein alternatively referred to as oil burdened corn. This extra oil in the corn reduces and may eliminate the need for the addition of the liquid fat to the feed.
Traditionally, oil burdened corn has been thought to contain increased level of phytic acid, as compared with levels in No. 2 yellow dent corn. Raboy et al (Journal of Heredity 1989: 80: 311-315) have reported however, that there is an apparent negative relationship between selection for oil and total phytic acid, phytic acid phosphorus and phosphorus per kernel, per germ and per endosperm of Illinois High Oil and Low Oil lines, as opposed to the previously expected apparent positive relationship on a concentration basis (i.e., mg constituent per g kernel, germ or endosperm). Raboy explains that the discrepancy between total contents per organ and concentration per organ results from the large divergence in organ dry weights exhibited between the Illinois High Oil (IHO) and Illinois Low Oil (ILO) seed used in his study; IHO germ being about twice the dry weight of ILO germ and ILO endosperm having nearly three times the dry weight of IHO is endosperm. In contrast to this trend for high oil being linked to lower phytic acid, Raboy also reports a consistent positive relationship between increasing protein selection and increasing amounts of phytic acid, phytic acid phosphorus and phosphorus. Thus, there is an apparent positive relationship between selection for protein and total phytic acid, phytic acid phosphorus and phosphorus per kernel, per germ and per endosperm of illinois high protein and low protein lines. This was maintained even when the data are expressed on a concentration basis (i.e., mg constituent per g kernel, germ or endosperm). Thus selection for protein and oil appears to divergently affect phytate content in seed.
As reports suggest an average increase of 0.38% protein with each 1% increase in oil (Han Y. Et al., 1987 Poultry Science 66:103-111; Keshararz, Poultry Pointers, pp6-7), it is uncertain from the art whether grains containing high oil, high protein and low phytic acid could be produced (Brewer, xe2x80x9cOptimum High Oil Corn Improves Poultry Rationsxe2x80x9d Poultry Digest, February/March 1998 pp30-31). Brewer states that while high oil corn is available as of 1998, varieties which are high in oil, high in protein and high in digestible phosphorus (i.e., low in phytic acid phosphorus), have yet to be developed.
The concentration of phytic acid in grain-based diets has long been of concern to humans and animal nutritionists, because evidence has shown that phytic acid acts to form insoluble salts with nutritionally important minerals that subsequently are not absorbed in the intestine. Phytic acid (myo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate)) is a form of phosphorus (P) in seeds which is stored in the form of phytate salts. Phytate salts have a negative nutritional impact on the animal because phosphorus bound to phytate is not available to the animal as a source of nutrition. Moreover, the animal does not retain the minerals such as Ca, Zn and the like and these needed minerals are excreted. Finally, the animal waste contain phytate P which then contributes to the surface and ground water pollution. If the grain is used for milling purposes then the milling by-products contain phytate P which then contributes to the surface and ground water pollution.
Swine, for example, lack the digestive enzyme (phytase) required to cleave the phosphorus from the phytate molecule and thus can not readily use phytate-phosphorus. Increasing the availability of phosphorus by elimination of the phytate salts binding the phosphorus would enable a reduction in dietary total phosphorus content without jeopardizing the animal""s health or production performance. Increasing the bioavailability of phosphorus results in a lower phosphorus content in the swine wastes, which is environmentally desirable.
In one attempt to release a portion of the phytate P present in maize and soybean meal the feed industry has added microbial phytase to the feed of animals. This method of dealing with phytate in the grain appears to partially decrease the phosphorus excreted by the animal. This research apparently led to further methods of degrading phytate in feed. One method includes adding an enzymatic cocktail and Aspergillus niger mycelium to feed. These components function to hydrolyze phytate present in the corn-soybean diet. Turkeys fed the enzymatic cocktail and the fungal mycellium showed enhanced performance and retention of P and Ca. These feed studies were planned to dephosphorylate the corn and soybean based feeds prior to consumption by the animal and thus reduce the P excreted. This method of dealing with phytate in the grain has the distinct disadvantage of adding labor and cost to the feed.
Mogen, in U.S. Pat. No. 5,593,963, describes production of a temperature stable phytase enzyme from Aspergillus in a corn or soy seed through genetic engineering techniques. The genetically produced phytase was designed to reduce the phytic acid content in animal feed by degrading the phytic acid being released from the grain and thus decrease the level of phosphorus excreted by the animal.
Low phytic acid mutant yellow dent corn seeds have been produced by Raboy and described in U.S. Pat. No. 5,689,054. This patent describes the discovery of a single gene, nonlethal lpa1 mutants in maize that cause the reduction of kernel phytic acid phosphorus by up to 95% over the wildtype phytic acid phosphorus levels. Raboy notes that while the mutants of his invention are phenotypically very similar to the wild-type, the mutants would need to be introduced in to a breeding program in order to introduce the low phytic acid trait in to a commercial line. Moreover, Raboy explains that the low phytic acid maize mutants of his invention are characterized by a small kernel dry weight reduction which could result in a reductionin productivity and that homozygous mutants may reduce or eliminate agronomically important characteristics. As Raboy et al (Journal of Heredity 1989) has indicated that divergent selection for high protein consistently produces higher phytic acid lines, it is unclear how the lpa1-R and lpa2-R mutations described in the Raboy patent in yellow dent corn will interact with genes for high-protein and oil-burdened corn seed. Thus one could not have predicted with certainty whether it would have been possible to maintain a high-protein oil burdened seed in combination with a low phytic acid mutant.
Although the feed industry has addressed both the need for more energy in the feed and the need for less phytate-phosphorus, the feed industry has not addressed the need for a method of providing, in a cost efficient manner, both the high nutrient density (i.e., high protein and high oil) and the low phytic acid in feed. There is a need to reduce the amount of phytate salts formed in feed and increase the amount of energy in feed without having to add phytase and liquid oil to feed. There remains a need, which has not been addressed, for a grain having a combination of increased protein and oil burden and low phytic acid levels. To reduce feed costs in animal production requires a nutritionally dense material that is cost-effective and environmentally friendly. Additionally, there remains a need for a feed containing an oil burdened, protein laden corn with low phytic acid levels which can be used for milling or for feed purposes.
An object of the present invention is to provide a nutrient-dense grain that contains both high levels of energy, through oil and improved amino-acid content, through protein, and low levels of phytic acid.
Another object of the present invention is to decrease the phosphate and/or phosphorus excretion of animals consuming the feed while increasing the energy levels per daily feed intake and bioavailability of minerals and other nutrients.
An object of the present invention is to provide an animal feed that contains both high levels of energy through oil and protein and low levels of phytic acid.
Still a further object of the present invention is to provide a highly nutrient dense feed source to livestock which has less phytic acid present then the same feed source when made with regular commodity corn (i.e., no. 2 yellow dent corns).
Still a further object of the present invention is to provide a high energy feed source to livestock containing sufficient supplies of any rate limiting amino acid which has less phytic acid present then the same feed source when made with regular commodity corn (no. 2 yellow dent corns).
It is another object of the invention to provide a method of reducing animal phosphorus waste and/or pollution, and subsequent algal and microbial blooms caused therefrom, which method includes feeding animals, such as pigs and chickens, the animal feed of the present invention.
In one embodiment, the present invention provides a non-lethal, mutant seed or grain of a cereal plant species, such as corn (maize), rice, barley and soy, having at least about 5% by dry weight, preferably at least about 6%, alternatively at least about 7%, oil; at least 11% by dry weight, preferably at least about 12%, alternatively at least about 13%, protein; and at least about a one third (33%) reduction in dry weight in the phytic acid amount (as measured by any of total phosphorus, phytic acid or phytic acid phosphorus), preferably at least about a one half (50%) reduction, alternatively at least about 60-70% reduction, relative to wild-type seed of said species. Where the seed of the present invention is corn, the comparison in reduction is preferably made relative to standard number (no.) 2 yellow dent corn.
In another embodiment, the present invention provides an increase in phosphorus availability of from 28% for yellow dent corn to greater than about 70%, preferably less than about 90%, alternatively about 80% to about 84-85%. Availability being the amount of utilizable phosphorus compared to total phosphorous from feed. The hybrid grain of the present invention is preferably a cross between useful inbreds and an inbred line ExSeed line U095 -lpa1-E (alternatively referred to as U095-E or U095py; deposited as strain designation EX1965py on Jul. 7, 1998 with American Type Culture Collection, 10801 University Blvd., Manassas, Va., 20110-2209 USA, under conditions of the Budapest Treaty, Accession No. 203034. Source U095-py 1656-W97-Florida-100) The xe2x80x9cExe2x80x9d or xe2x80x9cpyxe2x80x9d designation used herein indicates the introduction of a lpa1 mutation by the present inventors. A number of other crosses and inbreds can be employed. For example, the following female inbreds BD68py, TR306py, WD22py and TR329py were crossed with male inbreds U095py, UUOlpy, UE95py, TR335py and TR386py to make high-yielding hybrid combinations. Crosses with U095py are particularly preferred and the inbred U095py and hybrids made therefrom are specific embodiments of the present invention. The hybrid grain of the present invention characterized by having xe2x88x926% oil and 12% protein (or 3% more oil and 3% more protein than yellow dent corn) and at least about 33% reduction in phytic acid content.
In another embodiment, the present invention provides a feed containing a seed, as described herein, and at least one source of vitamins or minerals, containing, for example, any one or a mixture of at least two of calcium or phosphorus or salts thereof, vitamin A, vitamin D, vitamin E, B12, riboflavin, pantothenic acid, niacin, biotin, and trace minerals, such as iron, copper, manganese, zinc, iodine, and selenium, and/or additional feed additives, such as antibiotics, arsencials, chemotherapeutics, flavoring, antioxidants and plant extracts; said feed providing a nutritionally balanced diet and a greater amount of biologically useful phosphorus to an animal consuming said feed than does the same feed formed with wild-type seed of the species. The feed of the present invention may also contain amino acid additives, such as lysine and methionine.
In another embodiment, the present invention provides an improved feed which is otherwise formulated for swine or poultry but includes the seed, preferably corn seed, of the present invention.
In yet another embodiment, the present invention provides a method of increasing bioavailability of phosphorus from products containing wild-type seed of a species, said method including the steps of providing a seed containing product, such as a feed as described herein, for consumption, wherein the seed containing product contains a seed of the present invention, and feeding the seed containing product to an animal which will benefit from an increased bioavailability of phosphorus.
In a further embodiment, the present invention provides germplasm which will yield the seed of the present invention. In a preferred embodiment, the present invention provides corn germplasm which will yield the corn seed described herein.
In yet another embodiment, the present invention provides a plant produced from a seed of the present invention.
In yet a further embodiment, the present invention provides a seed of the present invention which is fully mature.
Still, further objects and advantages will become apparent from a consideration of the ensuing description.